Various forms of parts cleaning tanks containing cleaning fluid have been heretofore provided. Some of these tanks include heating elements for heating the cleaning fluid and other prior tanks include structure for discharging air upwardly through the cleaning liquid within the tank. However, few cleaning tanks include both heating elements and air injection structure and those cleaning tanks provided with both heating elements and air injection structure are not constructed in a manner whereby a predetermined circulation of cleaning fluid is established within the tank by the injection of air upwardly through the fluid and whereby a lower sump portion is provided in the lowest portion of the tank for precipitation of dirt particles from the cleaning liquid with the sump being at least partially isolated relative to the remainer of the interior of the tank disposed thereabove in a manner to reduce the turbulance of cleaning liquid within the sump area the for promotion of the desired precipitation of dirt particles from the liquid disposed within the tank.
Examples of cleaning tanks including some of the general structural and operational features of the instant invention are disclosed in U.S. Pat. Nos. 2,115,622, 2,151,354, 2,559,472, 2,597,931 and 2,720,210.